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Re: Subscript on plus expression
Posted:
Nov 19, 2012 5:05 PM
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Nasser --,
I'm using these as tensor indices.
Although Bob Hanlon offered a workaround (thanks Bob)
Format[Subscript[arg_Plus, k_]] :=
Subscript["(" <> StringJoin @@
Riffle[ToString /@ (List @@ arg),
" + "] <> ")", k]
Subscript[a + b + 2, k],
I think the folks at Mathematica should fix this and insert the parentheses.
The output of Subscript[Plus[a,b],k] should not be represented as
Plus[a,Subscript[b,k]]!
-- Dave
-----Original Message-----
From: Nasser M. Abbasi
Sent: Sunday, November 18, 2012 2:13 PM
Subject: Re: Subscript on plus expression
On 11/18/2012 3:03 AM, Dave Snead wrote:
> Hi,
>
> Mathematica fails to parenthesize the a+b in
> Subscript[Plus[a,b],k]
>
> so the output looks identical to
> Plus[a,Subscript[b,k]]
>
> Is this a bug?
> Is there an option to force the parentheses?
>
> Thanks in advance,
> Dave Snead
>
>
>
Actually, just typing
(a+b)
k
and then hitting ENTER will result in
a+b
k
i.e. the () are gone. Same effect you showed.
It might be because subscript are meant to be applied to an atomic symbol
and not combined expression like a+b. I do not know. I am not even sure
what (a+b)_k is supposed to mean, math wise. Is this meant to
be on the code or in a text cell? If it is in the code itself,
how will it be used?
--Nasser
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